EFun / RMartin / EVD / ...

Hi,

today I got my two efun's a Efun-C3500 (SLA) and an Efun-D5000 LiFePo4 (40Ah) with BMS.

Both are working only EFUN-D has a limited speed of 40km/h. Maybe someone can help me on that issue.
The rear wheel is turning quite powerfull and it is free running - so I think it isn't a mechanical problem.

There where also to other minor problems:
A 10A Charger was in the offer, but i got a 8A charger delivered. I'll ask EFUN to send me the correct one.

Aother minor topic was that tree screws are missing to fix the front "V" decoration and the windscreen correct.

One thing I really want to know ist what the function of the green button under the seat is?

About the EFUN-C performance I was really impressed. I did a shot test ride and I could reach 55km/h very fast.

It would be really great to get some hints or information, how to fix the limited speed problem of the efun-d.
I planned to do professional testing on this electric motor cycle, but if I can't meet the specification it will not make sense to test anything with this model.

Kind regards,
Gottfried

Judging by the R-Martin website I'm guessing they are pulling out of the large electric scooter market. The lithium EVD appears to have been dropped. And the warranty on the VRLA model is only 90 days!

Hmm. I hope I can find parts for my VRLA EVD in the years to come.

The switch has gone which switches off the power to the motor. This is the huge main electrical switch. The trouble is that I have a BMS with some lithium batteries and operating this switch always creates a massive spark which I fear will blow out some component on some occasion. So I would really like to know if I can just avoid using the switch when recharging, and join the ends together permanently?

In response to the very interesting offer by leading PRC EV manufacturer, E-Fun to contribute to the forum as a result of the somewhat controversial thread 'E-fun or Mountain Chen'. I thought it would be useful to create a separate thread where forum members could create a dialogue with this manufacturer.

E-Fun has kindly offered to discuss a wide range of commentary, from product technical details to import export problems. E-fun has expressed a real interest in benefiting from the vast technical and practical experience forum members possess. Here is a chance to talk directly to an EV maker. (John, we already value your contribution).

Amoyee Chen, we appreciate that it is not always possible for your staff to post in English, but if you feel more comfortable, please feel free to send me your material in Chinese, and I will post a (fairly) accurate translation.

Hi I'm new to the forum and Scooters. I'm buying one shortly and am looking a BE500 by Baja. How have these bikes stood up and what do people think of them?
Do they perform as advertised and how have you found the sevice to be? Thanks from a newbie!

I noticed, and have read on here about situations where the EVD seems to have less power than normal. I have experienced this myself, and found, as posted, that turning the EVD off and back on resets it to full power.

Is there a known way to get the EVD in this mode. I would like to be able to set it to a lower power setting or "economy" as it might be called on the XM bikes, so that a beginner can try out the EVD for a ride.

Has anyone found a way to consistently get the EVD in this low power mode?

Also has anyone tried replacing the throttle or tweaking anything to get more control when engaging the throttle. It seems to only work in one area on my throttle and is more or less on/off with little variance of power.

Thanks,

Whome

Howdy,

On saturday I ran a real world max range test. With fully charged batteries (pack was at 76V) a second rider and the lights on I wanted to do 40 miles (37 is the most I will need from a full charge.) The bike was fine and the low voltage light didnt even blink under full acceleration. (This is the 21 60AH lfp model.) Voltage on the pack was 69V. I decided to keep going until the light blinked under full accel. About 7 miles more and the light started blinking. So I went home (about 1/2 a mile.) I checked the voltage again and it was at 67.8V. My question then is. No light on accel = 69 V / 21 average (i know thats not the best way but I dont have test leads on the batts yet) = 3.28; light on under full accel = 67.8 v /21 = 3.22V.
Nominal voltage on lifepo is 3.2. So, since both of these readings are above 3.2 did I still have significant stored energy to continue and should I worry about the light under full acceleration? I want to get a feel for range and when to quit with about 30% life left (to keep it out of the danger zone for lower cells and to have 3000 cycles if needed.) Once I get my test leads on I will be able to tell how balanced the cells are. I can say the top 6 are all within .1V of each other but I cant easily get to the bottom 15. Oh and anyone not using their thundersky charger and want to sell it?
thanks
dex

Howdy,

I ordered a 60ah lfp EVD from rmartin last week (7/9/09) and am awaiting delivery. I have a few questions for those that have one. I want to verify that the batts are balanced but given the multitude of ways/opinions on the subject, I am not sure which way to go. Until the warranty is over I have to use the thundersky charger so my automatic options are limited. So, if someone has any advice on how to do it while keeping the warranty intact. I am assuming a few things here.

1. Batteries that start off balanced will slowly drift apart.
2. The further the drift, the faster they will spread.
3. It is possible to manually balance a battery pack given one has access to all the batts.

Here is my understanding of the problem. My battery pack has 21 batteries. Due to the varying AH capacities/internal battery quality they will not all charge/discharge at exactly the same rate. For instance I may have a battery in the pack that is 62AH and one that is 58AH or one that seems more stubborn to take a charge and is always undercharged. Ok let’s look at the stubborn one as an example. Let’s say for argument it’s just this one battery that is a problem in the whole pack. It is always charged less than the others because it won’t charge as fast. So while the others start out at 3.6V the "bad" one is at 3.3V. While that is in the "safe zone" for these batts (2.5V-4.2V) it is possible that it would drop below 2.5 while the rest of the pack are safe at 2.7 because it started out lower. This problem would never "fix" itself since the next charge would bring it up to 3.3 again and not 3.6. The reverse may also be true. I may have a bat that always is high compared to the others so one bat may go higher than 4.2 while the others are at 3.9 at the end of charge (to settle down around 3.6.) Again this wouldn’t be fixed with a new charge since its higher than the others when one started charging it.

Ok now I have a few questions.
1. Wouldn’t over time the high battery "charge" the rest of the batts in the pack and they would self balance (or vice versa the low batt gets a charge from the rest in the pack.) Sort of like water seeking the lowest point. Now, this doesn’t appear to happen given what I have read. I am not an electrical engineer so I am missing some of the basics on the subject. Just for my edification can someone explain why they don’t self balance (a Google search doesn’t really help all that turns up is balancing charges/bms systems.)

2. It seems to me this isn’t really any sort of magical problem that is difficult to solve manually. If there is a batt with too much charge on it, drain the charge off the battery until it is close enough to the other batts in the cell (say all have a .1V spread.) Then check it every month (or more often if one finds monthly isn’t frequent enough and rinse and repeat.) Or if there’s a stubborn cell get a 4.2V charger for lfp batts and charge it on its own until it’s close to the others. (I realize there may be low and high batts in the pack so both methods may need to be practiced on certain cells.) Am I being overly optimistic in thinking I can manually balance the batteries with these methods and they will stay close for the month? I.e. is it too much of a balancing act (pun) for a person to attempt oneself or too time consuming to be worthwhile?

I don’t have the scoot yet so I can’t tell how (un)lucky I am with the pack yet perhaps it won’t be much of a problem. I would also if someone has a bit of time like some guidance in what range I should be shooting for. I’ve read the specs on the batts and they say 2.5-4.2 but I would like to know what people are comfortable with in terms of swing between the low and high batt in the pack. I am assuming take readings fully charged and then depleted after my longest ride so I can determine if they are all in the safe zone and how far they drifted to then get safe max distance traveled.

Also, I would like some guidance with a single 4.2V lfp charger so I can address the stubborn ones if needed (or a bank charger if it turns out I have several low ones.) And also what would be a good safe method for draining off excess charge from the high ones (i.e. hook a light bulb up to it for a while etc.)

Once the warranty is up, I am thinking of going the bank charger way so each cell is charged on its own. Can anyone suggest a solution that can handle 21 cells. My thought is to get the batts close to full with the thundersky charger and then finish them off with something else that charges each cell on its own. But there may be better ways.
Thanks to everyone in advance for any help you could provide.
dex

I just purchased one of these RMartin EVT VRLA's online. It should ship out tommorow. I am hungry for info on it now though while I wait for it to arrive. There seems to be very little online.

Does it have regen?

Any mods done to increase torque or speed?

Any problems?

If you have any info or advice, or a link to another forum that has more EVT owners, I thank you in advance.

Whome

http://cgi.ebay.com/ebaymotors/R-Martin-Electric-Scooter-Moped-50-MPH-NO-GAS-NO-OIL_W0QQcmdZViewItemQQcategoryZ6722QQihZ020QQite...

I need it like a hole in the head, but would grab this if I were local in Arkansas.

Any forum member live nearby that can grab a deal on this one? I wish I won one like the seller did.